1. Field of the Invention
The invention relates to automated control of irrigation devices. More particularly, the invention relates to an irrigation controller with an embedded web server.
2. Description of the Related Art
Irrigation controllers are used to control the delivery of water to watering devices such as sprinkler heads and driplines. Controllers are typically configured to deliver water to sets of sprinklers arranged in watering zones to ensure that the sprinklers are provided with adequate water pressure. Watering by zones also permits each zone to be watered at different frequencies, durations, and times. Irrigation controllers control delivery of water to each set of the sprinklers by actuating the irrigation valves in a predetermined or selected sequence to accomplish the irrigation process.
A wide variety of controllers are commercially available for controlling the automatic operation of irrigation sprinklers in residential, industrial, and agricultural applications. These controllers vary in complexity and cost all the way from single-station, battery-powered units with few programming options that are mounted directly on a water valve, to complex, computer-based units capable of operating a complex irrigation system with many stations that require different operating parameters.
Two significant types of control systems used for landscape irrigation are depicted in FIGS. 1 and 2. FIG. 1 depicts a traditional stand-alone controller system 100 while FIG. 2 depicts a centralized control system 200.
Referring to FIG. 1, the depicted stand-alone controller system 100, which is typically wall mounted and used for smaller irrigation sites with four (4) to forty eight (48) irrigation devices, includes a controller 110 with user interface elements such as a keypad 120 and a liquid crystal display 130. With the user interface elements, a user can set up automatic watering programs, perform manual watering, and perform additional functions for irrigation control.
In the depicted example, the stand-alone controller 110 connects to one or more sensors 140 and irrigation solenoid valves 150. The sensors 140 may monitor multiple variables such as amount of rainfall, water flow, and power consumption. The sensors 140 provide such data to the stand-alone controller 110. The depicted stand-alone controller system 100 also includes a plurality of solenoid valves 150. Each solenoid valve 150 may control the flow of water to a particular watering zone.
Typically, the stand-alone controller 110 provides control signals to the solenoid valves 150 and may receive one or more sensor signals from the sensors 140 that provide input to various programmable features. Generally, such controllers tend to be difficult to set up or program in that the interface elements tend to be quite limited in functionality—particularly in cost sensitive installations. Additionally, in larger installations multiple stand-alone controllers must be used because the distance between the controller and valve stations is limited by a maximum amount of tolerable wiring impedance. Sites that utilize multiple stand-alone controllers are typically difficult to maintain in that the controllers must be individually programmed at their particular installation location.
FIG. 2 depicts an alternative to multiple stand-alone controllers 110, namely the centralized control system 200. As depicted, the centralized control system 200 includes a central computer 210 connected to a plurality of satellite controllers 220 which are in turn are connected to a number of solenoid valves 150. The centralized control system 200 generally includes various sense and/or control devices linked together via a communication channel 230.
The centralized control methodology depicted in FIG. 2 facilitates managing of large sites or multiple sites from a single location. A typical installation will contain multiple field controllers, or satellites 220, one or more sensors 140, and a single central control center containing a central computer 210.
The satellite controllers 220 are typically field devices, similar to the stand-alone controllers 110 that offer both valve control and various sensor interfaces. More sophisticated satellites also have a user interface for local programming. A major difference between the satellite controller 220 and the stand-alone controller 110 is the communication channel 230. The communication channel 230 interface allows the satellites 220 to communicate with the remote central computer 210. The type of medium used by the communication channel 230 varies depending on the requirements of each individual site. Typical centralized systems use twisted pair wire, radio modems, analog telephone modems, wireless communications (RF, VHF, UHF, microwave), fiber optics, power lines, telephone cables, cellular telephones, infrared, wireless pager systems, or television cables to carry the communication channel 230.
In managing large installations, the centralized system 200 has some advantages over using multiple stand-alone controllers. For example, the centralized system 200 significantly reduces the manpower and level of effort required to maintain a large installation. Problems at a satellite location can be instantly reported to the central computer. Also, complex watering schedules can be realized, such as those based on evapotranspiration, by utilizing the computer's graphical display and processing capabilities.
Despite the advantages of the centralized system, several problems and challenges still exist with such systems. The cost of a centralized system may be very high due to the dedicated equipment involved. For example, in a smaller site consisting of 5–10 satellite controllers, the costs associated with operating and maintaining a central computer may not be affordable, even though a centralized solution is preferred. Additionally, there is often a large and difficult learning curve for a system operator to fully understand and utilize the capabilities of the system. Moreover, the satellite controllers are generally simple receivers that can only communicate when specifically addressed by the central computer.
Given the aforementioned alternatives, a need exists for an irrigation controller containing an embedded web server that supports communication with a browser-equipped client such as a personal computer, PDA, or cell phone. Multiple irrigation controllers distributed in several locations may then be programmed from any authorized client that communicates via the internet or similar network means resulting in a graphically rich interface to the user. Beneficially, such an irrigation controller would simplify entry and maintenance of irrigation schedules, and facilitate distributed arrangements of master controllers and satellite controllers that coordinate with one another and communicate through the use of web pages and email. Preferably, such a controller would also be able to query a time server and thereby maintain an accurate time, and query a weather server and adjust the watering schedule in response to local weather conditions.